From patent specification CH 645 753, a circuit breaker can be used in an electrical high-voltage grid. This circuit breaker has a rotationally symmetrical interrupting chamber which is filled with a dielectrically inert gas, for example with SF6 gas, as quenching and insulating medium. The interrupting chamber has an arcing volume in which the quenching and insulating medium is ionized and heated up by the breaking arc burning between two arcing contact pieces. A part of this heated quenching and insulating medium flows off through an insulating nozzle into an exhaust volume where it is cooled and redirected by means of a cooling device. Mixing the heated quenching and insulating medium with the cold gas existing in the exhaust is possible only to a comparatively small extent since the predominant part of the cold gas is pressed out of the exhaust by the heated quenching and insulating medium before any significant mixing is possible. The flow resistance with which the cooling device opposes the flowing gas is kept as low as possible in this circuit breaker. The cooled and deionized quenching and insulating medium is then available again for further switching processes.
The cooling device has cooling plates which are elaborately shaped to aid the flow and must be elaborately held and, in addition, are manufactured of a metal which is resistant to burn-off loss or wear and is therefore comparatively expensive. Cooling of the heated quenching and insulating medium by mixing it with cold gas only occurs here to a very slight extent.